Footnotes

Source of funding: National Center for Complementary and Alternative Medicine; Office of Dietary Supplements; National Institute on Aging; National
Heart, Lung, and Blood Institute; University of Pittsburgh Alzheimer's Disease Research Center; Roena Kulynych Center for
Memory and Cognition Research; National Institute of Neurological Disorders and Stroke; Schwabe Pharmaceuticals donated Ginkgo
biloba tablets and placebos.

Commentary

Ginkgo biloba is a popular herbal supplement that is widely used in Europe and the USA for both treating and preventing dementia. However,
good quality evidence supporting its effectiveness is lacking. In 2007, a Cochrane review of 35 clinical trials (n = 4247)
suggested that Ginkgo biloba was ineffective for dementia.1 The study by DeKosky et al shows that Ginkgo biloba is no more effective than placebo for preventing dementia. It addresses many weaknesses identified in previous studies by
virtue of its large size (n = 3069) and relatively lengthy duration (⩾6 y exposure to Ginkgo biloba or placebo).

People often consider herbal therapies to be safe, even if they are not effective, and although I have previously suggested
that financial harm occurs if people spend money on ineffectual remedies,2 this study suggests that physical harm may also occur. There was a non-significant increase in haemorrhagic strokes in the
intervention group, and although this may be due to chance alone, it raises the question of “how safe is Ginkgo biloba?” This is an important question as the perception exists that herbal remedies are intrinsically safer than pharmaceutical
preparations.3 The clinical bottom line is that no evidence exists to support use of this supplement to prevent dementia. This fits into
the broader picture that Ginkgo biloba has no effect on slowing down progression of dementia in the early stages of disease.